From 3f64a0e3be2c9408f8256bd3aa9f0ce9e268982c Mon Sep 17 00:00:00 2001
From: Ted Kremenek <kremenek@apple.com>
Date: Fri, 21 May 2010 20:30:15 +0000
Subject: [PATCH] Fix crash in CFG construction for 'break' statements
appearing in statement expressions within the increment code of a for loop.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@104375 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Analysis/CFG.cpp | 15 ++++++++-------
test/Analysis/dead-stores.c | 12 ++++++++++++
2 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index c7eb53d3613..6f2cb41a6e4 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -985,6 +985,11 @@ CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) {
} else
LoopSuccessor = Succ;
+ // Save the current value for the break targets.
+ // All breaks should go to the code following the loop.
+ SaveAndRestore<CFGBlock*> save_break(BreakTargetBlock);
+ BreakTargetBlock = LoopSuccessor;
+
// Because of short-circuit evaluation, the condition of the loop can span
// multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
// evaluate the condition.
@@ -1032,10 +1037,9 @@ CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) {
{
assert(F->getBody());
- // Save the current values for Block, Succ, and continue and break targets
- SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ),
- save_continue(ContinueTargetBlock),
- save_break(BreakTargetBlock);
+ // Save the current values for Block, Succ, and continue targets.
+ SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ),
+ save_continue(ContinueTargetBlock);
// Create a new block to contain the (bottom) of the loop body.
Block = NULL;
@@ -1065,9 +1069,6 @@ CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) {
// represent the 'loop target' for looping back to the start of the loop.
ContinueTargetBlock->setLoopTarget(F);
- // All breaks should go to the code following the loop.
- BreakTargetBlock = LoopSuccessor;
-
// Now populate the body block, and in the process create new blocks as we
// walk the body of the loop.
CFGBlock* BodyBlock = addStmt(F->getBody());
diff --git a/test/Analysis/dead-stores.c b/test/Analysis/dead-stores.c
index 209ca6531cc..1c600276ba4 100644
--- a/test/Analysis/dead-stores.c
+++ b/test/Analysis/dead-stores.c
@@ -450,3 +450,15 @@ int f26_nestedblocks() {
return y;
}
+// The FOREACH macro in QT uses 'break' statements within statement expressions
+// placed within the increment code of for loops.
+void rdar8014335() {
+ for (int i = 0 ; i != 10 ; ({ break; })) {
+ for ( ; ; ({ ++i; break; })) ;
+ // Note that the next value stored to 'i' is never executed
+ // because the next statement to be executed is the 'break'
+ // in the increment code of the first loop.
+ i = i * 3; // expected-warning{{Value stored to 'i' is never read}}
+ }
+}
+
--
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